Method for producing power semiconductor module arrangement

ABSTRACT

A method is disclosed for producing a power semiconductor module that includes a substrate, at least one semiconductor body, a connecting element and a contact element. The method includes: arranging the substrate in a housing having walls; at least partly filling a capacity formed by the walls of the housing and the substrate with an encapsulation material; hardening the encapsulation material to form a hard encapsulation; and closing the housing, wherein the contact element extends from the connecting element through an interior of the housing and through an opening in a cover of the housing to an outside of the housing in a direction perpendicular to a first surface of a first metallization layer of the substrate.

TECHNICAL FIELD

The instant disclosure relates to a power semiconductor modulearrangement and to a method for producing a power semiconductor modulearrangement.

BACKGROUND

Power semiconductor module arrangements often include a substrate in ahousing. The substrate usually comprises a substrate layer (e.g., aceramic layer), a first metallization layer deposited on a first side ofthe substrate layer and a second metallization layer deposited on asecond side of the substrate layer. A semiconductor arrangementincluding one or more controllable semiconductor elements (e.g., twoIGBTs in a half-bridge configuration) may be arranged on a substrate.One or more contact elements, which allow contacting such asemiconductor arrangement from outside the housing, are usuallyprovided. Power semiconductor modules are known where the contactelements are arranged on the substrate and protrude in a direction thatis essentially perpendicular to the main surface of the substratethrough a cover of the housing. The section of the contact elementswhich protrudes out of the housing may be mechanically and electricallycoupled to a printed circuit board. Usually, the printed circuit boardcomprises openings and the contact elements are inserted through therespective openings. Often the power semiconductor module with thesemiconductor arrangement including the contact elements isprefabricated and a customer may mount his own customized printedcircuit board on the prefabricated power semiconductor module. Due totolerances which occur when mounting the contact elements on thesubstrate as well as tolerances which occur during fabrication of theprinted circuit board and the respective openings, the contact elementsand the openings may not be accurately aligned. Therefore, when mountinga printed circuit board to the power semiconductor module, great forcesmay be exerted on the contact elements. Over time, this may lead todamage to the power semiconductor module.

There is a need for a power semiconductor module arrangement thatprovides an increased mechanical robustness to prevent damage, and amethod for producing the same.

SUMMARY

A power semiconductor module arrangement includes a housing comprisingsidewalls and a cover, and a substrate arranged in the housing, thesubstrate comprising a dielectric insulation layer, a firstmetallization layer arranged on a first side of the dielectricinsulation layer, and a second metallization layer arranged on a secondside of the dielectric insulation layer, wherein the dielectricinsulation layer is disposed between the first and the secondmetallization layer. The power semiconductor module arrangement furtherincludes at least one semiconductor body mounted on a first surface ofthe first metallization layer which faces away from the dielectricinsulation layer, a connecting element arranged on and electricallyconnected to the first surface of the first metallization layer, acontact element that is inserted into and electrically connected to theconnecting element, wherein the contact element extends from theconnecting element through the interior of the housing and through anopening in the cover of the housing to the outside of the housing in adirection perpendicular to the first surface, and a hard encapsulationthat is arranged adjacent to the first metallization layer and that atleast partly fills the inside of the housing.

A power semiconductor module arrangement includes a substrate, at leastone semiconductor body, a connecting element and a contact element,wherein the substrate comprises a dielectric insulation layer, a firstmetallization layer arranged on a first side of the dielectricinsulation layer, and a second metallization layer arranged on a secondside of the dielectric insulation layer, wherein the dielectricinsulation layer is disposed between the first and the secondmetallization layer, and wherein the at least one semiconductor body ismounted on a first surface of the first metallization layer which facesaway from the dielectric insulation layer. The connecting element isarranged on and electrically connected to the first surface of the firstmetallization layer, and the contact element is inserted into andelectrically connected to the connecting element. A method for producingsuch a power semiconductor module arrangement includes arranging thesubstrate in a housing, wherein the housing comprises walls, at leastpartly filling a capacity formed by the walls of the housing and thesubstrate with an encapsulation material, hardening the encapsulationmaterial to form a hard encapsulation, and closing the housing, whereinthe contact element extends from the connecting element through theinterior of the housing and through an opening in the cover of thehousing to the outside of the housing in a direction perpendicular tothe first surface.

The invention may be better understood with reference to the followingdrawings and the description. The components in the figures are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention. Moreover, in the figures, likereferenced numerals designate corresponding parts throughout thedifferent views.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a conventional power semiconductormodule arrangement.

FIG. 2 is a cross-sectional view of an example of a power semiconductormodule arrangement.

FIG. 3 schematically illustrates different shore hardness scales.

FIG. 4 schematically illustrates different shore hardness scales and aRockwell scale.

FIG. 5 schematically illustrates the oxygen transmission coefficients ofvarious polymers.

FIGS. 6A and 6B schematically illustrate sections of exemplary powersemiconductor modules.

FIGS. 7A to 7C schematically illustrate an example of a method forproducing a power semiconductor module.

FIGS. 8A to 8C schematically illustrate another example of a method forproducing a power semiconductor module.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings. The drawings show specific examples in which theinvention may be practiced. It is to be understood that the features andprinciples described with respect to the various examples may becombined with each other, unless specifically noted otherwise. In thedescription as well as in the claims, designations of certain elementsas “first element”, “second element”, “third element” etc. are not to beunderstood as enumerative. Instead, such designations serve solely toaddress different “elements”. That is, e.g., the existence of a “thirdelement” does not require the existence of a “first element” and a“second element”. A semiconductor body as described herein may be madefrom (doped) semiconductor material and may be a semiconductor chip ormay be included in a semiconductor chip. A semiconductor body haselectrically connecting pads and includes at least one semiconductorelement with electrodes.

Referring to FIG. 1, a conventional power semiconductor modulearrangement is illustrated. The power semiconductor module arrangementincludes a substrate 10. The substrate 10 includes a dielectricinsulation layer 11, a (structured) first metallization layer 111arranged on a first side of the dielectric insulation layer 11, and asecond metallization layer 212 arranged on a second side of thedielectric insulation layer 11. The dielectric insulation layer 11 isdisposed between the first and the second metallization layer 111, 112.

Each of the first and second metallization layers 111, 112 may consistof or include one of the following materials: copper; a copper alloy;aluminium; an aluminium alloy; any other metal or alloy that remainssolid during the operation of the power semiconductor modulearrangement. The substrate 10 may be a ceramic substrate, that is, asubstrate in which the dielectric insulation layer 11 is a ceramic,e.g., a thin ceramic layer. The ceramic may consist of or include one ofthe following materials: aluminium oxide; aluminium nitride; zirconiumoxide; silicon nitride; boron nitride; or any other dielectric ceramic.The substrate 10 may be, e.g., a Direct Copper Bonding (DCB) substrate,a Direct Aluminium Bonding (DAB) substrate, or an Active Metal Brazing(AMB) substrate. Further, the substrate 10 may be an Insulated MetalSubstrate (IMS). An Insulated Metal Substrate generally comprises adielectric insulation layer 11 comprising (filled) materials such asepoxy resin or polyimide, for example. The material of the dielectricinsulation layer 11 may be filled with ceramic particles, for example.Such particles may comprise, e.g., Si₂O, Al₂O₃, AlN, or BrN and may havea diameter of between about 1 μm and about 50 μm. The substrate 10,however, may also be a conventional printed circuit board (PCB) having anon-ceramic dielectric insulation layer 11. For instance, a non-ceramicdielectric insulation layer 11 may consist of or include a cured resin.

One or more semiconductor bodies 20 may be arranged on the substrate 10.In particular, the one or more semiconductor bodies 20 may be arrangedon a first surface of the first metallization layer 111 which faces awayfrom the dielectric insulation layer 11. Each of the semiconductorbodies 20 arranged on the semiconductor substrate 10 may include adiode, an IGBT (Insulated-Gate Bipolar Transistor), a MOSFET(Metal-Oxide-Semiconductor Field-Effect Transistor), a JFBT (JunctionField-Effect Transistor), a HEMT (High-Electron-Mobility Transistor), orany other suitable controllable semiconductor element.

The one or more semiconductor bodies 20 may form a semiconductorarrangement on the substrate 10. In FIG. 1, only one semiconductor body20 is exemplarily illustrated. The one or more semiconductor bodies 20may be electrically and mechanically connected to the main substrate 10by an electrically conductive connection layer (not illustrated in FIG.1). Such an electrically conductive connection layer may be a solderlayer, a layer of an electrically conductive adhesive, or a layer of asintered metal powder (e.g., a sintered silver powder), for example.

The second metallization layer 112 of the semiconductor substrate 10 inFIG. 1 is a continuous layer. The first metallization layer 111 is astructured layer in the example illustrated in FIG. 1. “Structuredlayer” in this context means that the first metallization layer 111 isnot a continuous layer, but includes recesses between different sectionsof the layer. Such a recess is schematically illustrated in FIG. 1. Thefirst metallization layer 111 in this example includes two differentsections. Different semiconductor bodies 20 may be mounted to the sameor to different sections of the first metallization layer 111. There mayalso be sections of the first metallization layer 111 with nosemiconductor bodies 20 mounted thereon. Different sections of the firstmetallization layer 111 may have no electrical connection or may beelectrically connected to one or more other sections.

The substrate 10 may be arranged in a housing 40 to form a powersemiconductor module. In order to facilitate an electrical connection ofdifferent sections of the first metallization layer 111 and thesemiconductor bodies 20 and/or any other elements and componentsarranged on the first metallization layer 111 with each other as well aswith external components outside the housing 40 (e.g., a printed circuitboard), the power semiconductor module arrangement includes at least onecontact element 30. The at least one contact element 30 is arranged onthe substrate 10. Generally, the contact element 30 is arranged on thesame surface (here: first surface of the first metallization layer 111)as the semiconductor bodies 20. The contact element 30 may be a pin or awire, for example. The contact element 30 may consist of or include ametal or metal alloy. For example, the contact element 30 may consist ofor include copper. The contact element 30 is connected to the substrate10 by means of a connecting element 32. The connecting element 32 isarranged on the substrate 10, in particular on the first surface of thefirst metallization layer 111.

The connecting element 32 generally may include a solder layer, forexample. For example, the contact element 30 may be directly soldered tothe substrate 10. This, however, is only an example. As is illustratedin FIG. 1, the connecting element 32 may also include a sleeve or arivet. The connecting element 32 may be soldered, welded or glued to thesubstrate 10, for example. The connecting element 32 is configured toattach and electrically connect the contact element 30 to the substrate10. The connecting element 32 may comprise a tubular part (such as,e.g., a hollow bushing) that is configured to fit over and encompass afirst end of the contact element 30. This means that a first end of thecontact element 30 may be inserted into the connecting element 32.

The connecting element 32 and the first end of the contact element 30may form a press-fit connection, for example. Therefore, the contactelement 30 may include or may be a press-fit pin, for example. Theconnecting element 32 may include an appropriate counterpart for thepress-fit pin. While not connected to the counterpart, a press-fit pinhas a larger width than its counterpart. The width of the press-fit pinis a width in a direction parallel to an upper surface of thesemiconductor substrate 10. An upper surface of the semiconductorsubstrate 10 is a surface on which the connecting element 32 is mounted(e.g., first surface of the first metallization layer 111). During thepress-in process, the press-fit pin is pushed into the counterpart. Thisresults in a plastic deformation of the press-fit pin. When insertedinto the counterpart, the width of the press-fit pin is reduced. Onlysmall insertion forces are generally necessary with high holding forcesat the same time. The press-fit pin and the counterpart, after insertingthe press-fit pin, are firmly attached to each other. The reduced widthof the press-fit pin results in a force which counteracts thecompression of the press-fit pin. The contact element 30, therefore, maynot be easily detached from the connecting element 32. To furtherincrease the anchoring of the contact element 30 in the connectingelement 32 against forces in a direction perpendicular to the firstsurface of the first metallization layer 111 which pull the contactelement 30 away from the substrate 10, the contact element 30 may have arectangular, polygonal or other suitable cross-section instead of asimple rounded cross-section. Further, the contact element 30 maycomprise flanges (not illustrated) at its first end that are configuredto further secure the contact element 30 in the connecting element 32.Any other suitable connections between the contact element 30 and theconnecting element 32 are possible.

The contact element 30 protrudes from the substrate 10 and from theconnecting element 32 through the inside of the housing 40 and throughan opening in the cover of the housing 40 such that a second end of thecontact element 30 protrudes to the outside of the housing 40. In thisway, the contact element 30 may be contacted from the outside of thehousing 40.

For example, the second ends of the contact elements 30 may be connectedto a printed circuit board 50. The printed circuit board 50 may compriseopenings 51 and the contact elements 30 may be inserted into theopenings 51 of the printed circuit board 50. The printed circuit board50 may comprise conducting tracks (not illustrated) and a contactelement 30 may be electrically coupled to one or more other contactelements 30 by means of one or more conducting tracks. In this way, anelectrical connection may be provided between different sections of thefirst metallization layer 111, between different semiconductor bodies20, and/or between any other components arranged on the substrate 10.The contact elements 30 may be soldered to the printed circuit board 50,for example, to provide for a permanent and solid connection.

The power semiconductor module arrangement usually is prefabricated. Theprinted circuit board 50, however, is generally customer-specific and isattached to the power semiconductor module arrangement at a later stage.A printed circuit board 50 needs to match the semiconductor arrangementand, in particular, the positions of the contact elements 30. Inparticular, the positions of the openings 51 of the printed circuitboard 50 need to match the positions of the contact elements 30 suchthat the contact elements 30 may be easily inserted into the openings51. However, there are usually certain tolerances when mounting theconnecting elements 32 and the contact elements 30 to the substrate 10.Further, there are certain tolerances when forming the openings 51 inthe printed circuit board 50. There may be even further tolerances whenforming the openings in the cover of the housing 40 through which thecontact elements 30 protrude. The tolerances may be in the range of upto several 100 μm, for example. This means, that the second ends of thecontact elements 30 may not be accurately aligned with the openings inthe housing 40 and even further, with the openings 51 in the printedcircuit board. Therefore, the contact elements 30 are generally bendableto a certain degree such that they may still be inserted in the openings51 even if they are slightly misaligned to the openings 51. Therefore,rather high forces F may be exerted to the contact elements 30 whenbending the second ends of the contact elements 30 to fit into theopenings 51 of the printed circuit board 50. This is exemplarilyillustrated by means of a bold arrow in FIG. 1.

These forces F may influence the mechanical stability of the contactelements 30. For example, the electrical connections between the contactelements 30 and the connecting elements 32 or between the contactelements 30 and the printed circuit board 50 may have to withstand greatforces and may be damaged over time. This may influence the operation ofthe power semiconductor module arrangement. The contact elements 30 arearranged at a certain distance from each other. For example, a distancebetween two neighboring contact elements 30 may be less than 5 cm insmaller packages. In bigger packages, the distance between twoneighboring contact elements 30 may be 5 cm or more. Generally, themechanical robustness of such an arrangement worsens, the bigger thedimensions of the power semiconductor module arrangement and the greaterthe distance between two neighboring contact elements 30.

The present invention aims at improving the mechanical robustness ofsuch a power semiconductor module arrangement and may further increasethe robustness of the power semiconductor module arrangement againstlateral thermal cycles.

Referring to FIG. 2, the power semiconductor module arrangementgenerally corresponds to the arrangement as described with reference toFIG. 1 above. However, as is schematically illustrated in FIG. 2, thehousing 40 is at least partly filled with a hard encapsulation 60. Thehard encapsulation 60 is arranged adjacent to the substrate 10. Thismeans that the hard encapsulation 60 covers those parts of the firstmetallization layer 111 that are not covered by the connecting elements32, by the semiconductor bodies 20 or by any other components arrangedon the first metallization layer 111. The hard encapsulation 60 mayfurther cover the one or more semiconductor bodies 20 and the connectingelements 32 arranged on the substrate 10. The hard encapsulation 60further at least partially encloses the contact elements 30.

The hard encapsulation 60 may include a hard resin. For example, thehard encapsulation 60 may have a hardness of at least 40 Shore A, atleast 60 Shore A, or at least 50 Shore D. These, however, are onlyexamples. The hard encapsulation 60 may have any hardness that allowsthe hard encapsulation 60 to provide sufficient mechanical stability ofthe contact elements 30 that are at least partly embedded in the hardencapsulation 60.

FIG. 3 exemplarily illustrates a Shore 00 scale, a Shore A scale and aShore B scale as well as several examples of materials that have acertain hardness. The Shore 00 scale may be used to define materialsthat are less hard. The Shore 00 scale starts with materials that areextra soft such as “gummy” jelly candy, for example. The highest valueof 100 Shore 00 refers to medium hard materials such as tire treads, forexample. The Shore A scale is used for medium hard materials, startingat 0 Shore A for comparably soft materials. 20 Shore A refers to softmaterials such as rubber bands, for example. The scale ends with a valueof 100 Shore A which refers to comparably hard materials such asshopping cart wheels, for example. The Shore B scale is used for mediumhard to extra hard materials. While a value of 10 Shore B refers tomaterials that are medium hard such as tire treads, for example, a valueof 80 Shore B refers to materials which are extra hard such as hardhats, for example.

Further examples of different scales are exemplarily illustrated in FIG.4. FIG. 4 again exemplarily illustrates the Shore A scale which rangesfrom soft materials such as rubber bands to hard materials such asshopping cart wheels or golf balls, for example. The Shore A scalegenerally covers most rubbers and polyurethanes. FIG. 4 furtherillustrates a Shore D scale which overlaps with the Shore A scale to acertain degree. The Shore D scale partly covers rubbers andpolyurethanes as well as part of the known plastics such as Teflon,polypropylenes and polystyrenes, for example. Most plastics, which aregenerally harder than rubbers and polyurethanes, are covered by theRockwell R scale. The materials indicated in FIG. 4, however, are onlyexamples.

The material that is used for the hard encapsulation 60 may be chosenfrom any materials that have a hardness that is suitable to provide asufficient mechanical stability of the contact elements 30. For example,the hard encapsulation 60 may comprise a rubber or a polyurethane with aShore A value of 40 or more, or with a Shore A value of 60 or more, forexample. The hard encapsulation 60 may also include a polyurethane or aplastic with a Shore D value of 50 or more, for example. Generally, softresins with a lower hardness cannot provide the required mechanicalstability of the contact elements 30. The hard encapsulation 60 may alsocomprise any combination of suitable rubbers, polyurethanes, andplastics which is hard enough to provide sufficient stability.

In addition to the first material, the hard encapsulation 60 may furtherinclude a filler (not illustrated). For example, the filler may compriseparticles that are evenly distributed within the first material of thehard encapsulation 60. The filler may comprise a ceramic material suchas Al₂O₃ or SiO₂, for example. Alternatively, the filler may compriseinert porous plastic bodies, for example. The filler may furtherincrease the mechanical stability of the hard encapsulation 60 and,therefore, of the power semiconductor module.

The hard encapsulation 60 may not only provide stability, but mayfurther provide a barrier for corrosive gases, for example. Theabove-mentioned components, e.g., semiconductor bodies 20, connectingelements 32, solder layers, first metallization layer 111, as well asother components of the semiconductor arrangement inside the housing 40,may corrode when they come into contact with corrosive gases. Corrosivegases may include, e.g., sulfur or sulfur-containing compounds.Corrosive gases in the surrounding area of the power semiconductormodule arrangement may penetrate into the inside of the housing 40. Thehousings that are used for power semiconductor module arrangements areusually not fully protected against protruding gases. Further, corrosivegases may enter the housing 40 when the housing 40 is opened for anyreason or before the housing 40 is closed, for example. Inside thehousing 40, the corrosive gases may form acids or solutions, forexample, in combination with moisture that is present inside the housing40. When corrosive gasses come into contact with moisture, they may formions, e.g., alkali, earth alkali, or halogens. The corrosive gases orthe resulting solutions or ions may cause a corrosion of some or all ofthe components inside the housing 40. During the corrosion process, themetallic constituents of the components may be oxidized to theirrespective sulfides. The sulfide formation may alter the electricalproperties of the components or may result in the formation of newconductive connections and in short circuits within the powersemiconductor module arrangement.

Examples for corrosive gases are hydrogen sulfide (H₂S), carbonylsulfide (OCS), or gaseous sulfur (S₈). Generally, it is also possiblethat sulfur may enter the housing 40 as constituent of a solid materialor liquid.

Components including one or more metals such as copper (e.g., firstmetallization layer 111, connecting element 32, contact element 30, chippad metallization), silver (e.g., first metallization layer 111,connecting element 32, contact element 30, sintered layers, chip padmetallization), or lead (e.g. solder layers including leaded solder),may be particularly sensitive to corrosion. Other metals such asaluminium, for example, may have a thin oxide layer covering theirsurface area, which may provide at least a certain amount of protectionagainst corrosive gases.

FIG. 5 exemplarily illustrates the oxygen transmission coefficient ofvarious polymers. The oxygen transmission coefficient or oxygentransmission rate (OTR) is the measurement of the amount of oxygen gasthat passes through a substance or material over a given period. It ismostly determined for non-porous materials, where the mode of transportfor oxygen is diffusion. The oxygen transmission coefficient is usuallyalso indicative for the amount of corrosive gases that may enter thehousing 40. A material that is less permeable for oxygen is usually alsoless permeable for other gases. The diagram illustrated in FIG. 5 showsthe oxygen transmission coefficients for silicone rubber, naturalrubber, low-density polyethylene (LDPE), polystyrene (PS), polypropylene(PP), polycarbonate (PC), polyvinyl acetate (PVAc), polyethyleneterephthalate (A-PET), polyvinylchloride (PVC), Ny6, polyvinyl fluoride(PVF), polyvinylidene chloride (PVDC), polyacrylonitrile (PAN), ethylenevinyl alcohol (EVOH), and polyvinyl alcohol (PVA).

The material used for the hard encapsulation 60 may combine theadvantages of a material having at least a certain hardness and amaterial providing a sufficient barrier for corrosive gasses. Forexample, the material of the hard encapsulation 60 may have an oxygentransmission coefficient of less than 10⁻¹⁰, or less than 10⁻¹².

Referring to FIG. 6A, the hard encapsulation 60 may form a layer on thesubstrate 10. Any semiconductor bodies 20 or other components arrangedon the substrate 10 may be arranged between the substrate 10 and thehard encapsulation 60. Between the substrate 10 and the cover of thehousing 40, the contact elements 30 may have a first length x1, that is,in a direction perpendicular to the first surface of the firstmetallization layer 111. The total length of the contact elements 30 isgreater than the first length x1, as part of the contact elements 30protrudes out of the housing 40. The layer of hard encapsulation 60 mayhave a thickness x2 in a direction perpendicular to the first surface ofthe first metallization layer 111. The thickness x2 of the hardencapsulation 60 may be between 20% and 80% of the first length x1 ofthe contact elements 30. That is, the hard encapsulation 60 may cover20-80% of the part of the contact elements 30 that is arranged insidethe housing 40. This, however, is only an example. According to anotherexample, the thickness x2 of the hard encapsulation 60 is between 40%and 60% of the first length x1 of the contact elements 30.

The hard encapsulation 60 may have an essentially even surface in adirection facing away from the substrate 10 and the semiconductor bodies20. This is schematically illustrated in FIGS. 2 and 6A. As isschematically illustrated in FIG. 6B, it is also possible that the hardencapsulation 60 may have an uneven surface. For example, in an areasurrounding a contact element 30, the hard encapsulation 60 may have afirst thickness x2, as has been explained with reference to FIG. 6Aabove. In other areas, the hard encapsulation 60 may have a secondthickness x3 which is less than the first thickness x2. For example, thehard encapsulation 60 may have the first thickness x2 in a first radiusr around each of the contact elements 30. The first radius r may be upto 1 mm, up to 2 mm, up to 5 mm, or up to 1 cm, for example. In areasthat are outside this radius r around the contact elements 30, the hardencapsulation 60 may have the second thickness x3 which is less than thefirst thickness x2. In this way, less material is needed to form thehard encapsulation 60 and the mechanical stability of the contactelements 30 may still be provided. The second thickness x3 may bebetween 10% and 60%, or 20% to 40% of the first length x1 of the contactelements 30, for example. The second thickness x3, however, depends on athickness of the semiconductor bodies 20 and any other componentsmounted on the substrate 10. The hard encapsulation 60 should at leastcompletely cover any components mounted on the substrate 10.

Referring to FIGS. 7A to 7C, an example of a method for producing apower semiconductor module arrangement is described. Referring to FIG.7A, the housing may comprise walls 42. The substrate 10 with thesemiconductor arrangement arranged thereon may be arranged within thewalls 42 of the housing. As no cover is provided at this stage and thehousing is open at the top, encapsulation material 62 may be filled intothe capacity formed by the walls 42 and the substrate 10. Theencapsulation material 62 may have a liquid, viscous or gel-likeconsistency. After filling the encapsulation material 62 into thehousing, a hardening process may follow (FIG. 7B). During this hardeningprocess, some or all of the liquid may be removed from the encapsulationmaterial 62. Thereby, the encapsulation material 62 is hardened andforms the hard encapsulation 60. In a following step, which isschematically illustrated in FIG. 7C, the housing may be closed with acover 44. The cover 44 may comprise openings, as has been describedabove, through which the contact elements 30 protrude.

Referring to FIGS. 8A to 8C, a further example of a method for producinga power semiconductor module arrangement is described. Referring to FIG.8A, the housing 40 comprises walls and a cover and the cover comprisesat least one further opening through which the encapsulation material 62is inserted into the housing 40. No contact element 30 protrudes throughthis further opening. The substrate 10 with the semiconductorarrangement arranged thereon may be arranged within the housing 40. Theencapsulation material 62 may be filled into the capacity formed by thehousing 40 and the substrate 10. The encapsulation material 62 may havea liquid, viscous or gel-like consistency. After filling theencapsulation material 62 into the housing 40, a hardening process mayfollow (FIG. 8B). During this hardening process, some or all of theliquid may be removed from the encapsulation material 62. Thereby, theencapsulation material 62 is hardened and forms the hard encapsulation60. In a following step, which is schematically illustrated in FIG. 8C,the opening in the housing 40 may be closed. The housing 40 may compriseopenings, as has been described above, through which the contactelements 30 protrude.

FIGS. 7A-7C and 8A-8C illustrate exemplary methods for forming a hardencapsulation 60 with an even surface. To form a hard encapsulation 60with an uneven surface, as has been explained with reference to FIG. 6Babove, internal frames (not illustrated) may be arranged on thesubstrate 10 before filling in the encapsulation material 62 (honeycombprinciple). For example, internal frames may be arranged at a firstdistance around each contact element 30, wherein the first distanceequals the radius r of the area having the first thickness x2. In thisway, different sections may be formed and encapsulation material 62 maybe filled in each of the different sections with different heights x2,x3. Another possibility for forming a hard encapsulation 60 withdifferent heights x2, x3 in different areas is to insert displacementbodies (not illustrated) before filling in the encapsulation material62. A hard encapsulation 60 having different heights x2, x3, however,may be formed in any other suitable way.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat a variety of alternate and/or equivalent implementations may besubstituted for the specific embodiments shown and described withoutdeparting from the scope of the present invention. This application isintended to cover any adaptations or variations of the specificembodiments discussed herein. Therefore, it is intended that thisinvention be limited only by the claims and the equivalents thereof.

What is claimed is:
 1. A method for producing a power semiconductormodule that includes a substrate, at least one semiconductor body, aconnecting element and a contact element, the substrate comprising adielectric insulation layer, a first metallization layer arranged on afirst side of the dielectric insulation layer, and a secondmetallization layer arranged on a second side of the dielectricinsulation layer, the dielectric insulation layer being disposed betweenthe first and the second metallization layers, and the at least onesemiconductor body being mounted on a first surface of the firstmetallization layer which faces away from the dielectric insulationlayer, the connecting element being arranged on and electricallyconnected to the first surface of the first metallization layer, thecontact element being inserted into and electrically connected to theconnecting element, the method comprising: arranging the substrate in ahousing having walls; at least partly filling a capacity formed by thewalls of the housing and the substrate with an encapsulation material;hardening the encapsulation material to form a hard encapsulation; andclosing the housing, wherein the contact element extends from theconnecting element through an interior of the housing and through anopening in a cover of the housing to an outside of the housing in adirection perpendicular to the first surface.
 2. The method of claim 1,wherein the encapsulation material comprises a liquid or solvent and hasa liquid, viscous or gel-like consistency, and wherein hardening theencapsulation material comprises removing some or all of the liquid orsolvent from the encapsulation material.
 3. The method of claim 1,wherein closing the housing comprises closing the housing with a cover.4. The method of claim 1, wherein closing the housing comprises closingan opening within a cover of the housing.
 5. The method of claim 1,wherein the hard encapsulation has a hardness of at least 40 Shore A. 6.The method of claim 1, wherein the hard encapsulation has a hardness ofat least 60 Shore A.
 7. The method of claim 1, wherein the hardencapsulation has a hardness of at least 50 Shore D.
 8. The method ofclaim 1, wherein the hard encapsulation comprises a rubber, apolyurethane and/or a plastic.
 9. The method of claim 1, wherein thecontact element has a first length between the substrate and the coverof the housing in a direction perpendicular to the first surface of thefirst metallization layer, wherein the hard encapsulation has a firstthickness in a direction perpendicular to the first surface of the firstmetallization layer, and wherein the first thickness of the hardencapsulation is between 20% and 80% of the first length of the contactelement or between 40% and 60% of the first length of the contactelement.
 10. The method of claim 9, wherein the first thickness of thehard encapsulation is between 40% and 60% of the first length of thecontact element.
 11. The method of claim 1, wherein the contact elementhas a first length between the substrate and the cover of the housing ina direction perpendicular to the first surface of the firstmetallization layer, wherein the hard encapsulation has a firstthickness in a direction perpendicular to the first surface of the firstmetallization layer in areas within a radius around the contact element,wherein the hard encapsulation has a second thickness in a directionperpendicular to the first surface of the first metallization layer inareas outside the radius around the contact element, and wherein thefirst thickness is greater than the second thickness.
 12. The method ofclaim 11, wherein the first thickness of the hard encapsulation isbetween 20% and 80% of the first length of the contact element, andwherein the second thickness of the hard encapsulation is between 10%and 60% of the first length of the contact element.
 13. The method ofclaim 1, wherein the hard encapsulation is configured to provide abarrier for corrosive gases.
 14. The method of claim 13, wherein thehard encapsulation has an oxygen transmission coefficient of less than10⁻¹⁰.
 15. The method of claim 14, wherein the oxygen transmissioncoefficient of the hard encapsulation is less than 10⁻¹².
 16. The methodof claim 1, wherein the hard encapsulation comprises a filler that isevenly distributed in the hard encapsulation.
 17. The method of claim16, wherein the filler comprises Al₂O₃, SiO₂, and/or inert porousplastic bodies.
 18. The method of claim 1, wherein the connectingelement comprises a tubular part configured to fit over and encompass afirst end of the contact element.
 19. The method of claim 18, whereinthe contact element comprises, at the first end, a press-fit pin,wherein the connecting element comprises a counterpart for the press-fitpin of the contact element, and wherein the first end of the contactelement and the connecting element form a press-fit connection when thecontact element is inserted into the connecting element.